A long-term study directed at the isolation, characterization and structural elucidation of new and potentially useful cancer chemotherapeutic drugs from marine animals has been proposed. Support would be used to isolate and characterize anti-cancer agents from confirmed active extracts of marine invertebrates, and marine vertebrates. Maximum effort would be devoted to marine animal species affording extracts with outstanding confirmed level activity (T/C greater than 150) in the National Cancer Institute's murine PS lymphocytic leukemia screening system. As each problem is solved (or placed in a lower priority due to decreasing or lost activity during fractionation guided by bioassay) it would be replaced by another (of high priority) from a current collection of over 300 marine animal specied giving extracts with a confirmed level of activity. The lower animals represent an exceedingly productive source of new cancer chemotherapeutic drugs and all effort will be directed at making such new substances available to the Division of Cancer Treatment, National Cancer Institute.